As our friends at Nielsen put it succinctly this week, mobile phones have reached a critical mass around the world.

In the latest head-to-head comparisons of PC vs. mobile engagement, mobile now captures close to 40 percent of all time spent online. What’s more, mobile is already well ahead of PCs when it comes to engagement with maps, music, weather and, not surprisingly, social networks.

What’s truly significant about this reality, however, is that these developments may represent only the tip of the iceberg for mobile’s future.Nowhere is this practical industry optimism more apparent than in comScore’s recently published “2013 Mobile Future in Focus.” If you haven’t yet downloaded the whitepaper, it comes highly recommended by those who have.

comScore’s projections for mobile’s growth in 2013 and beyond follow a watershed year for mobile in 2012. Last year, the U.S. smartphone market finally eclipsed 50 percent market penetration and now enters the “late majority” stage of the technology adoption curve, comScore says.

“The number of smartphone subscribers has increased 29 percent from a year ago and 99 percent from two years ago,” the report reads.

Smartphones have surpassed 125 million U.S. consumers and tablets are now owned by more than 50 million. We have now crossed into the Brave New Digital World – a new paradigm of digital media fragmentation in which consumers are always connected.

At the start of 2013, MMW was teeming with headlines based on the huge predictions some in our industry were touting for mobile this year. Barely eight weeks into 2013 and plenty of these projections have already been revised to the upside.

To check out the new comScore whitepaper and weigh their prognostications against your own, click here.